refactor(render): flush alpha at retail walk barriers

src/AcDream.App/Rendering/RetailPViewPassExecutor.WalkLeaf.cs

@@ -189,10 +189,8 @@ internal sealed partial class RetailPViewPassExecutor
 /// <item><see cref="ClearInteriorDepth"/>/<see cref="DrawExitSeals"/> →
 /// caller-supplied actions (the renderer owns the pass scope and the
 /// root-flood seal iteration; the adapter only provides the turns).</item>
-/// <item><see cref="AlphaBarrier"/> → <c>FlushLandscapeAlphaFartherThan</c>
+/// <item><see cref="AlphaBarrier"/> → <c>FlushLandscapeAlpha</c>, retail's
-/// (the <c>DrawBuilding</c> barrier; retail's flush-all
+/// flush-all <c>FlushAlphaList(0f)</c> @0x0059f30b.</item>
-/// <c>FlushAlphaList(0f)</c> @0x0059f30b is the FW4 adjudication
-/// candidate recorded on the driver's interface).</item>
 /// </list>
 /// </summary>
 internal sealed class WalkProductionLeafRenderer : IWalkFrameLeafRenderer
@@ -257,6 +255,5 @@ internal sealed class WalkProductionLeafRenderer : IWalkFrameLeafRenderer
     public void DrawPunchFan(WalkPolygon worldPolygon, int activeViewIndex) =>
         _passes.DrawWalkPunchFan(_frame, _clipAssembly, worldPolygon, activeViewIndex);
 
-    public void AlphaBarrier(float viewerDistance) =>
+    public void AlphaBarrier() => _passes.FlushLandscapeAlpha();
-        _passes.FlushLandscapeAlphaFartherThan(viewerDistance);
 }

src/AcDream.App/Rendering/Walk/WalkFrameDriver.cs

@@ -180,17 +180,11 @@ internal interface IWalkFrameLeafRenderer
     /// that view's slice planes.</summary>
     void DrawPunchFan(WalkPolygon worldPolygon, int activeViewIndex);
 
-    /// <summary><c>RetailAlphaQueue.FlushFartherThan</c>'s <c>DrawBuilding</c>
+    /// <summary>Retail <c>D3DPolyRender::FlushAlphaList(0f)</c>
-    /// barrier — retail's own call site is
+    /// @0x0059f30b. The walk is positional: only farther cells have submitted
-    /// <c>D3DPolyRender::FlushAlphaList(0f)</c> @0x0059f30b, a FLUSH-ALL, not
+    /// alpha when a building turn fires, so this is a full drain with no
-    /// a distance-gated flush; this stage keeps the DISPATCHED
+    /// synthetic viewer-distance threshold.</summary>
-    /// <c>FlushFartherThan(viewerDistanceTo(building))</c> shape (the two
+    void AlphaBarrier();
-    /// coincide under the walk's far-to-near landscape order, since a nearer
-    /// emitter has not been inserted into the alpha queue yet — see
-    /// <c>RetailAlphaQueue.FlushFartherThan</c>'s own doc comment) and flags
-    /// the 0f/address detail as an FW4 adjudication candidate rather than
-    /// silently reinterpreting the dispatched design.</summary>
-    void AlphaBarrier(float viewerDistance);
 }
 
 /// <summary>
@@ -353,8 +347,8 @@ internal readonly struct WalkFrameEvent
     internal static WalkFrameEvent PunchFan(WalkPolygon worldPolygon, int activeViewIndex) =>
         new(WalkFrameEventKind.PunchFan, activeViewIndex, 0, 0f, worldPolygon);
 
-    internal static WalkFrameEvent AlphaBarrier(float viewerDistance) =>
+    internal static WalkFrameEvent AlphaBarrier() =>
-        new(WalkFrameEventKind.AlphaBarrier, 0, 0, viewerDistance, null);
+        new(WalkFrameEventKind.AlphaBarrier, 0, 0, 0f, null);
 
     internal static WalkFrameEvent LandscapeCellParticles(uint cellId) =>
         new(WalkFrameEventKind.StaticParticles, 0, cellId, 0f, null);
@@ -711,7 +705,7 @@ internal sealed class WalkFrameDriver : IWalkEventSink, IWalkLookInViewSource
                     _leafRenderer.DrawPunchFan(e.Polygon!, e.IntArg);
                     break;
                 case WalkFrameEventKind.AlphaBarrier:
-                    _leafRenderer.AlphaBarrier(e.FloatArg);
+                    _leafRenderer.AlphaBarrier();
                     break;
                 case WalkFrameEventKind.ClearInteriorDepth:
                     _leafRenderer.ClearInteriorDepth();
@@ -840,7 +834,7 @@ internal sealed class WalkFrameDriver : IWalkEventSink, IWalkLookInViewSource
     void IWalkEventSink.OnBuildingTurn(WalkBuilding building)
     {
         ArgumentNullException.ThrowIfNull(building);
-        IWalkBuildingFrameContext ctx = RequireOpenFrame();
+        RequireOpenFrame();
         VisitedBuildings.Add(building);
 
         // D3DPolyRender::FlushAlphaList(0f) @0x0059f30b — retail's alpha
@@ -848,7 +842,7 @@ internal sealed class WalkFrameDriver : IWalkEventSink, IWalkLookInViewSource
         // look-ins) follows this call; the building's own shell content is
         // appended only once that pass completes (OnBuildingShellTurn).
         MarkIfGrown();
-        _events.Add(WalkFrameEvent.AlphaBarrier(ctx.ViewerDistanceTo(building)));
+        _events.Add(WalkFrameEvent.AlphaBarrier());
 
         _currentDcStage = WalkDrawStage.LookInStatic;
     }

tests/AcDream.App.Tests/Rendering/Walk/WalkFrameDriverTests.cs

@@ -60,7 +60,7 @@ public sealed class WalkFrameDriverTests
             log.Add($"PUNCH:{worldPolygon.Vertices.Length}@v{activeViewIndex}");
         }
 
-        public void AlphaBarrier(float viewerDistance) => log.Add($"ALPHA:{viewerDistance:F2}");
+        public void AlphaBarrier() => log.Add("ALPHA");
 
         public void DrawStaticParticles(IReadOnlySet<uint> ownerIds)
         {
@@ -447,7 +447,7 @@ public sealed class WalkFrameDriverTests
             // submit at the shell turn, after the shell content flushes.
             new[]
             {
-                "ALPHA:12.50", "PUNCH:4@v0", "SHELL:00000104",
+                "ALPHA", "PUNCH:4@v0", "SHELL:00000104",
                 "FLUSH:1:LookInStatic", "FLUSH:1:Dynamic",
                 "CELL-PARTICLES:00000104:ca,cb",
                 "FLUSH:1:BuildingShell", "PARTICLES:c9",